mailboxes.db vs IMAP client irregularities

[Stephen Ingram]

I'm running 2.4.13 from the invoca rpms on CentOS 5.8. I recently had
an issue with a folder in a mailbox that would not show any
subfolders. I created a new folder 'folder2' and moved all of the
subfolders to it and then performed a reconstruct on the new set of
folders and everything worked. Now I deleted the old folder 'folder'
from the file system and then (after it wouldn't go away from the
cyradm listing) used cyr_dbtool to manually remove it (and the
subfolders) from the mailboxes.db file. The old folders and subfolders
are now gone, however, I can't (using the IMAP client) rename
'folder2' back to 'folder' as when I do, the subfolders are not
visible.

I've dumped the mailboxes.db file to a flat file to look and see if
there is anything in there that wasn't visible in cyradm or using
cyr_dbtool show. Everything is as expected except there are some
DELETED.user.xxx.folder entries at the top. Are you not allowed the
create folders with the same name you've just deleted? Where are these
DELETED folders actually stored and how long does it take them to go
away? (I'm not using delayed expunge.)

If that's not the issue, then is there some other file besides
mailboxes.db that might contain bad information or is this a bug in
the system?

Steve